Impact of Architectural Details on the Transmission of Airborne Pollutants between Flats in Residential High-Rise Buildings

Abstract

The interflat cross-contamination of air pollutants such as coronavirus disease 2019 (COVID-19) in built environments has become a growing concern. This study investigates the effect of the geometrical details of building facades on wind-induced airborne pollutant transmission routes in high-rise buildings. Parametric studies of different external-shading elements of buildings, wind speeds, and wind directionality are considered. A high-resolution computational fluid dynamics (CFD) using a realizable k-epsilon turbulence closure model is employed to analyze the airflow field. For the windward single-sided ventilation case, the reentry ratio from the source room to the other unit under prevailing, 45°, and 90° wind directions are quantified, and the possible interflat cross-contamination routes are simulated. The transmission route is highly dependent on a building's architectural features, wind speed, wind directionality, and location of the source room. The result shows that external shading plays a crucial role in mitigating or accelerating airborne pollutant transmissions. A building with horizontal shadings restricts vertical cross-contamination between flats, but it allows horizontal interflat cross-contamination. However, buildings with vertical shadings reduce the risk of horizontal cross-contamination but increase the probability of vertical cross-contamination. The egg-crate shading minimizes the risk of both horizontal and vertical cross-contamination. A smooth facade building is highly susceptible to cross-contamination for a wide range of wind directionality. Therefore, this study is helpful for architecture and building science for the analysis of airborne pollutants, for tracing the routes of cross-contamination in residential buildings, and for reducing the risk of transmission of respiratory diseases such as COVID-19.